1. Field of the Invention
The present invention relates to an information distribution system such as a video-on-demand (VOD) system. More particularly, the present invention relates to a method and apparatus for migrating users between information server modules in a manner minimizing disruption of content streams being provided to the user.
2. Description of the Background Art
VOD systems providing content encoded according to the various Moving Pictures Experts Group (MPEG) standards are known. For example, a first standard known as MPEG-1 refers to ISO/IEC standards 11172, which is incorporated herein by reference in its entirety. A second standard known as MPEG-2 refers to ISO/IEC standards 13818, which is incorporated herein by reference in its entirety. Additionally, a compressed digital video system is described in the Advanced Television Systems Committee (ATSC) digital television standard document A/53, incorporated herein by reference.
The most important characteristic of a video on demand system is the experience of a user receiving content via that system. That is, a user ideally selects desired content and the system provides the desired content to the user in a timely manner and at a quality level consistent with the user's expectations. Failure to meet the user expectations in terms of image quality, sound quality, system latency or other factors results in a less than satisfying experience to the user. Unfortunately, video demand systems and other systems are subject to periodic operational anomalies such that a user experience may be adversely impacted. For example, in the case of a user receiving a content stream such as a movie or television program via a server, an operational anomaly occurring within the server or within apparatus supporting the server may result in the cessation of the content stream to the user. This is, obviously, a very undesirable condition.